# Chichibu Unkai Watcher — Detect the Sea of Cloud

> Detect the Sea of Cloud (iPhone/iPad app by Uda Toyokazu.)

- Source: https://appshunter.io/ios/app/chichibu-unkai-watcher/id1541135503 (this page in markdown: same URL + `.md`)
- Developer: [Uda Toyokazu](https://appshunter.io/developer/1527354994)
- Category: Weather
- Price: Free
- Age rating: 4+
- Requires: iOS 14.1 · 8 MB
- Languages: English, Japanese
- Released: 2020-11-23
- Data updated: 2026-07-24
- User reviews in markdown: https://appshunter.io/ios/app/chichibu-unkai-watcher/id1541135503/reviews.md

## What is Chichibu Unkai Watcher?

Chichibu-city, Japan is famous for the “SEA OF CLOUD” (Unkai in Japanese). Chichi Unkai Watcher can detect the SEA OF CLOUD by the Machine Learning technology. It downloads pictures from the Chichibu Unkai Live Camera, execute AI classification and detect UNKAI. It can notify alerts when UNKAI is detected.


## Version history (last 5 releases)

### 3.0.1 — 2022-01-01

Improved accuracy of recognition.
A minor bug fix.

### 3.0.0 — 2021-12-10

Improved accuracy of recognition.
Weather data source has been changed to Amedas
Links to weather reports by JMA and Yahoo Weather have been added.
Links to Twitter hash tags (Japanese) have been added.
Tap on the main image to show/hide Date, Time, Confidence Level, details has been implemented.

### 2.0.0 — 2021-06-22

The latest 24 hour weather charts of Chichibu-city have been added.

### 1.2.1 — 2021-05-30

Fixed a bug that image download fails at specific time.

### 1.2.0 — 2021-05-29

Fixed minor bugs.

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## More apps by Uda Toyokazu

- [NegaViewer](https://appshunter.io/ios/app/negaviewer/id1527354992)
- [CatRecorder](https://appshunter.io/ios/app/catrecorder/id1528492163)

All apps by Uda Toyokazu: https://appshunter.io/developer/1527354994

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-07-24.*